So check in the debugger and look at the line:
object productkin = gridView1.GetRowCellValue(gridView1.FocusedRowHandle, gridView1.Columns["ProductDescrption"]);
Look at the
FocusedRowHandle
, and
gridView1.Columns["ProductDescrption"]
and see what cell they are trying to return.
We can't - we don't have access to your data.